Sail fails to decode some APNGs about sail HOT 7 CLOSED

You can try the latest master with blending of grayscale images.

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I agree there are some blending issues. I've just fixed a memory corruption issue (at least on MSVC 2019) on free() and allowed blending for BPP16-GRAYSCALE-ALPHA and BPP32-GRAYSCALE-ALPHA pixel formats. I will probably continue looking into it (sorry cannot guarantee).

Regarding the 8-bit greyscale and alpha, with blending image: it has three frames:

1. The first frame is hidden.
2. The second frame is black (gray component: 0, alpha: 255), blending mode: over.
3. The 3rd frame consists of semi-transparent white pixels which will look like gray after blending with black pixels (gray component: 255, alpha: 128), blending mode: over.

https://philip.html5.org/tests/apng/tests.html specifies that the image should be rendered as This should be solid grey. but I have a question why 🤔 The second frame is black. The third (blended) frame is gray. I would expect flashing black and gray frames and this is what I see currently in the local fixed SAIL version.

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If the image viewer respects num_plays in the acTL chunk then it should just play once and pause on the last frame.

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Oh, I see. This explains a lot. The next rc will have blending of grayscale frames and I'll add num_plays as a special property for those who are interested.

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Did you install sail through vcpkg?

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No, I built it from source.

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Please reopen if needed

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